Kake Airport
Aircraft Accident/Incident Report

Kake, Alaska 99830
Monday, June 11, 2007 15:30 AKD

The commercial certificated pilot was conducting scheduled passenger flights. On the flight prior to the accident flight, the passengers complained of a smell the pilot thought might be exhaust. After landing, he examined the engine for exhaust leaks. Finding none, he proceeded with the return flight. While departing the airport he heard a loud bang, the passenger cabin started to fill with smoke, and he saw fire at his feet. He reduced the throttle, and landed on the airport runway. In his haste to depart the airplane, he did not turn the fuel off, and he left the electric fuel boost pump on. He said after exiting the airplane, he saw a large pool of fuel forming under the airplane, and smoke continued to emanate from the passenger cabin door. The pooled fuel ignited, burning the airplane. The passengers said they first noticed the smoke in the rear of the passenger cabin, and that the smoke propagated forward until they could no longer see the pilot. During the examination of the airplane, the NTSB investigator found that approximately a 4" X 6" piece of the right side exhaust manifold at the rear of the engine was missing. The edges of the manifold, where the piece was missing, had scalloped fractures and long straight tears consistent with fatigue fractures and failure. Additional fractures were found in other areas of the exhaust system. The hot exhaust gasses burned a hole in the heater shroud at the point where it attaches to the scat tubing which provides heated air to the vents in the rear of the passenger cabin. The hot exhaust gasses were deflected by the firewall onto the engine fuel line attached to the engine driven fuel pump mounted on the left rear of the engine, burning the fuel line through. The electric fuel boost pump provided pressurized fuel to the engine driven pump, which resulted in fuel continuing to flow and pooling on the ground. According to airplane records, the exhaust system had been inspected in accordance with the operator's approved inspection program, 2.9 flight hours prior the accident.

A fractured exhaust manifold, which resulted in an in-flight fire, and the inadequate inspection of the airplane by the operator's maintenance personnel.